Objective:To investigate the clinical effect of 3D printing combined with O-arm navigation assisted posterior hemivertebrae resection and orthopedic fixation in the treatment of congenital cervicothoracic scoliosis.Methods:A retrospective study was conducted on the clinical data of 14 patients with congenital cervicothoracic kyphosis caused by hemivertebra treated in Henan Provincial People's Hospital from January 2015 to June 2021, including 9 males and 5 females, aged 8.9±3.2 years (range, 1-15 years). Operation time, intraoperative blood loss and fusion stage were recorded. Intraoperative O-arm scanning and postoperative CT scanning were performed to evaluate the accuracy of nail placement. The cervicothoracic scoliosis Cobb angle, compensatory scoliosis Cobb angle, local kyphosis Cobb angle, torticollis angle, T 1 tilt angle and clavicular angle were measured before operation, model design, 1 week after operation and at the last follow-up to evaluate the effect of surgical design, intraoperative orthosis and the correction loss at follow-up. The Society for Scoliosis Research-22 (SRS-22) questionnaire was used to evaluate the functional and treatment effect. At the last follow-up, the osteotomy fusion was evaluated by Eck criterion. Results:All patients successfully completed the operation, the operation time was 228.5±41.8 min, the intraoperative blood loss was 355.6±46.7 ml, and the number of fusion segments was 5.5±0.8. Follow-up duration was 35.5±13.2 months. A total of 140 pedicle screws were inserted, with an accuracy of 97.1% (136/140). The Cobb angle of cervicothoracic scoliosis was 53.9°±17.9° preoperatively, 11.3°±4.4° in the model design, 10.8°±2.6° one week postoperatively, and 14.5°±3.5° at the last follow-up, with statistical significance ( P<0.001). The preoperative and postoperative one week difference was statistically significant ( P<0.001) with a correction rate of 78.6%±6.7%. The Cobb angle of compensatory scoliosis was 33.1°±12.1° before surgery, 11.9°±2.4° for model design, 10.5°±3.4° for one week after surgery, and 14.1°±2.5° for the last follow-up, with statistically significant differences ( P<0.001). The postoperative correction rate was 65.2%±16.2%. The Cobb angle of local kyphosis was 27.8°±9.8° preoperatively, 10.1°±2.1° in the model design, 9.8°±1.9° one week postoperatively, and 12.7°±1.6° at the last follow-up, with statistical significance ( P<0.001). The preoperative and postoperative one week difference was statistically significant ( P<0.001) with a correction rate of 59.2%±18.9%. The preoperative and postoperative one week difference was statistically significant ( P<0.001) with a correction rate of 78.6%±6.7%. The neck tilt angle was 20.6°±6.7° preoperatively, 6.2°±1.9° in the model design, 5.9°±2.1° one week postoperatively, and 7.1°±1.4° at the last follow-up, with statistical significance ( P<0.001). The preoperative and postoperative one week difference was statistically significant ( P<0.001) with a correction rate of 70.0%±11.1%. The T 1 inclination angle was 20.2°±5.8° preoperatively, 11.5°±3.1° in the model design, 10.2°±2.3° one week postoperatively, and 9.5°±3.0° at the last follow-up, with statistical significance ( P<0.001). The preoperative and postoperative one week difference was statistically significant ( P<0.001) with a correction rate of 53.2%±10.4%. There was no significant difference between preoperative design and actual measurement one week after surgery ( P>0.05). At the last follow-up, the scores of self-image (4.6±0.7), mental health (4.7±0.6) and treatment satisfaction (4.6±0.6)in SRS-22 scale were significantly improved compared with those before operation ( P<0.05). The symptoms of hemivertebra ipilateral C 8 nerve root injury occurred in 1 patient, who was treated conservatively with dehydration, hormones and nutraceutical drugs, and recovered to normal at 3 months follow-up. At the last follow-up, the appearance of the head, neck and shoulders of the patients was improved compared with that before surgery, the bone grafts have achieved osseous fusion in all patients. All fusion were grade I by Eck criterion. No complications such as serious neurological or vascular injury occurred during perioperative period. No pseudoarthrosis formation, internal fixation loosening or fracture occurred during follow-up. Conclusion:The application of 3D printing combined with O-arm navigation assistance technology in posterior hemivertebra resection and correctional surgery for cervicothoracic hemivertebra deformities can display the deformities in advance, stereoscopic and real-time, accurately place pedicle screws and complete hemivertebra resection, improve surgical safety and deformity correction rate.

Objective:To compare the effect of O-arm assisted and free-hand pedicle screw placement in the treatment of AO type C thoracolumbar fracture.Methods:A retrospective cohort study was used to analyze the clinical data of 34 patients with type C thoracolumbar fracture admitted to Henan Provincial People′s Hospital from January 2018 to June 2021, including 23 males and 11 females; aged 42-63 years [(50.4±7.4)years]. The fracture was located at T 11 in 4 patients, T 12 in 10, L 1 in 12, L 2 in 6, T 11~12/L 1 in 1 and T 12/L 1 in 1. Posterior reduction and internal fixation was carried out for all patients, of whom 18 were treated with O-arm assisted pedicle screw placement (navigation group) and 16 with free-hand pedicle screw placement (free-hand group). The operation time, single screw placement time, intraoperative bleeding volume, operation mode and screw placement accuracy were compared between the two groups. The kyphotic Cobb angle, visual analogue score (VAS) and American Spinal Injury Association (ASIA) score were compared between the two groups before operation, at 1 week after operation, at 3 months after operation and at the last follow-up. Postoperative complications were observed. Results:All patients were followed up for 12-29 months [(16.8±6.1)months]. There was no significant difference between the two groups in the operation time, intraoperative bleeding volume and operation mode (all P>0.05). The single screw placement time was (9.4±1.6)minutes in navigation group, but was (10.8±1.5)minutes in free-hand group ( P<0.05). The screw placement accuracy was 97.4% in navigation group, but was 81.5% in free-hand group ( P<0.01). The kyphotic Cobb angle and VAS had no significant differences between the two groups before operation (all P>0.05). The kyphotic Cobb angle in navigation group and free-hand group was (4.3±1.1)° and (5.9±1.1)° at 1 week after operation, (4.4±1.2)° and (5.7±1.3)° at 3 months after operation, and (4.4±1.2)° and (6.8±0.9)° at the last follow-up, decreased significantly from that before operation [(21.8±3.1)°, (22.2±3.2)°] (all P<0.01). The kyphotic Cobb angle in navigation group was significantly lower than that in free-hand group at 1 week, 3 months after operation and at the last follow-up (all P<0.01). The VAS in navigation group and free-hand group was (3.2±0.7)points and (4.1±0.7)points at 1 week after operation, (2.4±0.6)points and (3.0±0.8)points at 3 months after operation, and (1.8±0.9)points and (2.6±0.7)points at the last follow-up, decreased significantly from that before operation [(8.4±0.8)points, (8.3±0.9)points] (all P<0.01). The VAS in navigation group was significantly lower than that in free-hand group at 1 week, 3 months after operation and at the last follow-up (all P<0.01). The ASIA score showed no significant difference within and between the two groups before operation, at 1 week, 3 months after operation and at the last follow-up (all P>0.05). Postoperative incision infection occurred in 1 patient in both groups ( P>0.05). Implant failure such as loosening or displacement was not observed in navigation group, and only occurred in 2 patients in free-hand group ( P>0.05). Conclusion:Compared with free-hand pedicle screw placement, O-arm assisted pedicle screw placement in the treatment of AO type C thoracolumbar fracture has advantages of rapid and accurate screw placement, good reduction and notable pain relief.

Objective:To investigate the clinical efficacy and precautions of O-arm combined with navigation-assisted steotomy and hemivertebra resection for congenital cervicothoracic hemivertebra.Methods:From February 2016 to October 2020, the clinical data of 12 patients with cervicothoracic hemivertebra admitted in Henan Provincial People's Hospital were retrospectively analyzed, including 5 males and 7 females, aged 9.4±2.6 years (range, 4-15 years). Intraoperative neural monitoring system was used to ensure the safety of surgical correction process and O-arm navigation system assisted the implantation of pedicle screws,hemivertebra resection, and scoliosis deformity correction. Postoperative CT was used to evaluate the accuracy of screw placement, and routine preoperative and postoperative X-ray films of the full-length spine in standing position were taken to measure the coronal and sagittal Cobb angles. The correction rate of scoliosis and kyphosis, internal fixation, shoulder height difference and bone graft fusion were calculated at the final follow-up.Results:A total of 108 pedicle screws were inserted in 12 patients, and the screw placement accuracy rate was 96.3% (104/108). The follow-up time was 37.9±10.2 months (range, 24-61 months). The number of fused segments was 5.4±1.1 (range, 4-7). One week after surgery, the correction rate of Cobb angle was 78.5%±3.2% for scoliosis and 70.1%±5.4% for kyphosis. There were statistically significant differences in side and kyphosis Angle and Scoliosis Research Society (SRS)-22 score between preoperative and 1 week after surgery ( P<0.05). There was no significant difference between the operation and the last follow-up ( P>0.05). At the last follow-up, all the 12 patients achieved gradeⅠ fusion. SI was 2.4±0.8 cm before operation, 1.0±0.6 cm at 1 week after operation, and 0.7±0.5 cm at last follow-up, and the difference was statistically significant ( F=38.30, P<0.001). No pseudojoint formation, significant loss of correction Angle, or rupture of internal fixation relaxant occurred during the operation or during follow-up. Conclusion:O-arm combined with navigation-assisted steotomy and hemivertebra resection for the treatment of congenital cervicothoracic hemivertebra has the advantages of good orthopedic effect, reduced radiation exposure and fewer complications, and accurate pedicle screw implantation and hemivertebra resection.

Objective:To investigate the clinical effect of anterior cervical release and posterior fixation in the treatment of irreducible atlantoaxial dislocation with retropharyngeal internal carotid artery.Methods:Thirteen patients with irreducible atlantoaxial dislocation of retropharyngeal internal carotid artery from January 2015 to July 2019 were treated with anterior cervical release and posterior fixation. There were 8 males and 5 females, aged from 34 to 65 years with an average of 46.1±12.6 years. Positive, lateral and dynamic X-ray films, MR and CTA were performed before operation. There were 4 cases with bilateral retropharyngeal internal carotid artery and 9 cases with unilateral retropharyngeal internal pharyngeal artery. The time of operation, the amount of bleeding and intraoperative and postoperative complications were recorded. The main observations were Japanese Orthopaedic Association (JOA) score, atlantodental interval (ADI), Chamberlain line (CL), and changes in the morphology of the retropharyngeal internal carotid artery and implant fusion.Results:All the operations completed successfully. The operation time was 210-260 min, the average was 245±21 min; the blood loss was 350-600 ml, the average blood loss was 490±107 ml. There was no injury of internal carotid artery, vertebral artery, spinal cord or nerve root during the operation. All patients were followed up for 9 to 24 months, with an average of 15.1±6.2 months. Preoperative JOA score was 6.9±2.3 points, 1 month after operation was 13.5±2.5 points, and the last follow-up was 14.3±2.1 points. The difference was statistically significant ( F=30.91, P<0.001). The difference between 1 month after operation and before operation was statistically significant ( P<0.001), and the improvement rate of JOA score was 75.6%±15.2%. There was no significant difference between the last follow-up and 1 month after operation ( P>0.05). The preoperative ADI was 8.9±2.2 mm, 1 month after operation was 1.1±0.8 mm, and the last follow-up was 1.2±0.9 mm. The difference was statistically significant ( F=114.69, P<0.001). The difference between 1 month after operation and before operation was statistically significant ( P<0.001), and ADI had returned to normal level. There was no significant difference between the last follow-up and 1 month after operation ( P>0.05). The preoperative CL was 11.7±4.8 mm, 1 month after operation was 1.6±2.1 mm, and the last follow-up was 1.8±2.3 mm. The difference was statistically significant ( F=34.19, P<0.001). The difference between 1 month after operation and before operation was statistically significant ( P<0.001), and the position of odontoid process returned to normal level. There was no significant difference between the last follow-up and 1 month after operation ( P>0.05). Bone graft fusion was received at 6 to 12 months after operation, with an average of 10.2 months. Conclusion:CTA examination should be performed before anterior release of atlantoaxial dislocation to understand the position and shape of internal carotid artery. Anterior cervical release combined with posterior bone graft fusion is an effective method for the treatment of irreducible atlantoaxial dislocation with retropharyngeal internal carotid artery without increasing the risk of internal carotid artery injury.

Objective:To compare the efficacy of posterior atlas uniaxial and polyaxial screw instrumentation and fusion with bone graft for Gehweiler type IIIb atlas fracture.Methods:A retrospective cohort study was performed to analyze the clinical data of 36 patients with Gehweiler type IIIb atlas fracture admitted to Henan Provincial People′s Hospital from January 2015 to October 2020. There were 29 males and 7 females, with age range of 23-82 years [(48.8±15.5)years]. All patients were treated with posterior atlas screw-rod internal fixation and fusion with bone graft, of which 14 received atlas uniaxial screw internal fixation (uniaxial screw group) and 22 received atlas polyaxial screw internal fixation (polyaxial screw group). The operation time and intraoperative blood loss were compared between the two groups. The atlas fracture union rate and atlantoaxial posterior arch bone fusion rate were compared between the two groups at 3 months and 6 months after operation. The anterior atlantodental interval (ADI), basion-dens interval (BDI) and lateral mass displacement (LMD) were compared between the two groups to evaluate the reduction of fracture fragments before operation, at 1, 3, 6 months after operation and at the last follow-up. At the same time, the visual analogue scale (VAS) and neck dysfunction index (NDI) were compared between the two groups to evaluate neck pain and functional recovery. The postoperative complications were observed.Results:All patients were followed up for 12-44 months [(27.2±9.9)months]. There was no significant difference in operation time or intraoperative blood loss between the two groups (all P>0.05). The atlas fracture union rate and atlantoaxial posterior arch bone fusion rate were 85.7% (12/14) and 78.6% (11/14) in uniaxial screw group at 3 months after operation, insignificantly different from those in polyaxial screw group [72.7% (16/22) and 77.3% (17/22)] (all P>0.05). All patients in the two groups achieved bone union and fusion at 6 months after operation. There was no significant difference in ADI between the two groups before and after operation (all P>0.05). The BDI in the two groups did not differ significantly before operation ( P>0.05), but a significantly higher value was found in uniaxial screw group at 1, 3, and 6 months after operation and at the last follow-up [(5.9±1.3)mm, (5.8±1.3)mm, (5.9±1.2)mm and (5.8±1.2)mm] than in polyaxial screw group [(3.1±0.6)mm, (3.1±0.6)mm, (3.1±0.6)mm and (3.1±0.6)mm] (all P<0.01). The two groups did not differ significantly before operation ( P>0.05), but LMD at 1, 3, and 6 months after operation and at the last follow-up was (1.6±0.8)mm, (1.5±0.8)mm, (1.5±0.7)mm and (1.5±0.9)mm in uniaxial screw group, significantly lower than that in polyaxial screw group [(4.8±1.6)mm, (4.6±1.6)mm, (4.9±1.6)mm and (4.9±1.6)mm] (all P<0.01). There was no significant difference in VAS between the two groups before operation ( P>0.05). The VAS at 1, 3, and 6 months after operation and at the last follow-up was 3.0(3.0, 4.0)points, 2.0(1.0, 2.0)points, 1.0(0.8, 2.0)points and 1.0(0.0, 1.3)points in uniaxial screw group and was 3.5(3.0, 4.0)points, 2.0(2.0, 3.0)points, 2.0(1.0, 2.0)points and 2.0(1.0, 3.0)points in polyaxial screw group. In comparison, the VAS scored much lower in uniaxial screw group than in polyaxial screw group at 6 months after operation and at the last follow-up (all P<0.01). There was no significant difference in NDI between the two groups before operation ( P>0.05). The NDI at 1, 3, and 6 months after operation and at the last follow-up was 34.9±6.3, 23.4±6.2, 13.9±2.7 and 9.4±2.8 in uniaxial screw group and was 33.2±6.1, 24.4±6.3, 18.1±4.1 and 12.7±3.2 in polyaxial screw group, showing a significantly lower NDI in uniaxial screw group than in polyaxial screw group at 6 months after operation and at the last follow-up (all P<0.01). The complication rate was 21.4% (3/14) in uniaxial screw group when compared to 22.7% (5/22) in polyaxial screw group ( P>0.05). Conclusion:For Gehweiler type IIIb atlas fracture, both techniques can attain atlas fracture union and atlantoaxial posterior arch bone fusion, but the posterior atlas uniaxial screw instrumentation and fusion is superior in reduction of atlas fracture displacement and lateral mass separation, neck pain relief and functional improvement.

Osteoporotic vertebral compression fracture (OVCF) can lead to lower back pain and may be even accompanied by scoliosis, neurological dysfunction and other complications, which will affect the daily activities and life quality of patients. Vertebral augmentation is an effective treatment method for OVCF, but it cannot correct unbalance of bone metabolism or improve the osteoporotic status, causing complications like lower back pain, limited spinal activities and vertebral refracture. The post-operative systematic and standardized rehabilitation treatments can improve curative effect and therapeutic efficacy of anti-osteoporosis, reduce risk of vertebral refracture, increase patient compliance and improve quality of life. Since there still lack relevant clinical treatment guidelines for postoperative rehabilitation treatments following vertebral augmentation for OVCF, the current treatments are varied with uneven therapeutic effect. In order to standardize the postoperative rehabilitation treatment, the Spine Trauma Group of the Orthopedic Branch of Chinese Medical Doctor Association organized relevant experts to refer to relevant literature and develop the "Guideline for postoperative rehabilitation treatment following vertebral augmentation for osteoporotic vertebral compression fracture (2022 version)" based on the clinical guidelines published by the American Academy of Orthopedic Surgeons (AAOS) as well as on the principles of scientificity, practicality and advancement. The guideline provided evidence-based recommendations on 10 important issues related to postoperative rehabilitation treatments of OVCF.

Objective:To observe the effect of insertion of in-out-in axis pedicle screws on the vertebral artery in the posterior occipitocervical surgery for atlantoaxial subluxation or instability.Methods:The data of 52 patients with atlantoaxial dislocation or instability were analyzed who had been treated by internal fixation with in-out-in pedicle screws in the posterior occipitocervical surgery from January 2015 to February 2021 at Department of Spine and Spinal Cord Surgery, Henan Provincial People's Hospital. There were 30 males and 22 females, aged from 17 to 65 years (mean, 41.2 years). There were 26 cases of unilateral vertebral artery high-riding, 3 cases of bilateral high-riding, 19 cases of unilateral narrow pedicle due to C2 and C3 fusion, and 4 cases of bilateral narrow pedicles. X-ray, CTA and MRI were performed before and 3 days after surgery. The patients' clinical symptoms were recorded. CTA was used to measure the diameter of the vertebral artery at the transverse foramina of C 2 and C 3 and to observe the effect of in-out-in screws on the morphology of the vertebral artery. X-ray and CT examinations were performed at 6 months after surgery to observe the bone fusion. Results:The surgery went on uneventfully in all the patients. In the 9 cases undergoing anterior and posterior surgery, the operation time averaged 271.2 min (from 213 to 352 min) and the bleeding volume 471.5 mL (from 230 to 830 mL). In the 43 cases undergoing posterior surgery, the operation time averaged 171.6 min (from 131 to 226 min) and the bleeding volume 395.9 mL (from 170 to 660 mL). There was no such complication as spinal or vascular injury. The CTA reexamination 3 days after surgery showed that the diameter of the vertebral artery was (2.92±0.55) mm and (3.04±0.54) mm, respectively at the cervical 2 and 3 transverse foramina, showing no significant change compared with the preoperative values [(2.91±0.68) mm and (3.11±0.50) mm] ( P>0.05) and that the vertebral artery was displaced externally and inferiorly in 21 cases. Follow-ups for all patients ranged from 7 to 24 months (mean, 11 months). At 6 months after surgery, bone fusion was observed by imaging and no breakage or displacement of the internal fixation was observed. Conclusion:The in-out-in pedicle screws in the posterior occipitocervical surgery may have little impact on the vertebral artery, leading to reliable clinical outcomes.

Osteoporotic thoracolumbar fracture in the elderly will seriously reduce their quality of life and life expectancy. For osteoporotic thoracolumbar fracture in the elderly, spinal reconstruction is necessary, which should comprehensively consider factors such as the physical condition, fracture type, clinical characteristics and osteoporosis degree. While there lacks relevant clinical norms or guidelines on selection of spinal reconstruction strategies. In order to standardize the concept of spinal reconstruction for osteoporotic thoracolumbar fracture in the elderly, based on the principles of scientificity, practicality and progressiveness, the authors formulated the Clinical guideline for spinal reconstruction of osteoporotic thoracolumbar fracture in elderly patients ( version 2022), in which suggestions based on evidence of evidence-based medicine were put forward upon 10 important issues related to the fracture classification, non-operative treatment strategies and surgical treatment strategies in spinal reconstruction after osteoporosis thoracolumbar fracture in the elderly, hoping to provide a reference for clinical treatment.

Objective:To analyze the incidence and epidemiological characteristics of traumatic spinal cord injury in China in 2018.Methods:Multi-stage stratified cluster sampling was used to randomly select hospitals capable of treating patients with spinal cord injury from 3 regions，9 provinces and 27 cities in China to retrospectively investigate eligible patients with traumatic spinal cord injury admitted in 2018. National and regional incidence rates were calculated. The data of cause of injury，injury level，severity of injury，segment and type of fracture，complications，death and other data were collected by medical record questionnaire，and analyzed according to geographical region，age and gender.Results:Medical records of 4，134 patients were included in this study，with a male-to-female ratio of 2.99∶1. The incidence of traumatic spinal cord injury in China in 2018 was 50.484 / 1 million （95% CI 50.122-50.846）. The highest incidence in the Eastern region was 53.791 / 1 million （95% CI 53.217-54.365）. In the whole country，the main causes of injury were high falls （29.58%），as well as in the Western region （40.68%），while the main causes of injury in the Eastern and Central regions were traffic injuries （31.22%，30.10%）. The main injury level was cervical spinal cord in the whole country （64.49%），and the proportion of cervical spinal cord injury in the Central region was the highest （74.68%），and the proportion of lumbosacral spinal cord injury in the Western region was the highest （32.30%）. The highest proportion of degree of injury was incomplete quadriplegia （55.20%），and the distribution pattern was the same in each region. A total of 65.87% of the patients were complicated with fracture or dislocation，77.95% in the Western region and only 54.77% in the Central region. In the whole country，the head was the main combined injury （37.87%），as well as in the Eastern and Central regions，while the proportion of chest combined injury in the Western region was the highest （38.57%）. A total of 32.90% of the patients were complicated with respiratory complications. There were 23 patients （0.56%） died in hospital，of which 17（73.91%） died of respiratory dysfunction. Conclusions:The Eastern region of China has a high incidence of traumatic spinal cord injury. Other epidemiological features include high fall as the main cause of injury cervical spinal cord injury as the main injury level，incomplete quadriplegia as the main degree of injury，head as the main combined injury，and respiratory complications as the main complication.

Objective:To explore the scheme of accurate pelvic osteotomy parameters and to analyze the feasibility and efficacy of 3D printing navigation plate in developmental dysplasia of the hip surgery.Methods:From January 2015 to December 2017, a total of 18 children with DDH underwent computer-assisted Salter pelvic osteotomy (computer-assisted osteotomy group) and 25 children with DDH who underwent conventional Salter pelvic osteotomy (conventional osteotomy group) were selected for retrospective analysis. There were 11 males and 32 females with an average age of 3.2±2.5 (range 1-11) years. According to International Hip Dysplasia Institute (IHDI) classification, there were 20 cases of type 1, 9 of type 2, 12 of type 3 and 2 of type 4. All patients were unilateral dislocation, including 18 cases on the left and 25 on the right. All children underwent pelvic CT examination before operation. Further, the proximal femur was surgically corrected during the operation. According to the acetabular rotation angle (ATA) and bony acetabular index (BAI), the computer-assisted osteotomy group simulated the operation with Mimics software made 3D printing navigation plate through which an accurate osteotomy scheme was developed. The two groups were compared in operative duration, intraoperative blood loss, Japanese Orthopaedic Association (JOA) hip joint score. Acetabular index (AI), central edge (CE) angle, and acetabulum head index (AHI) were compared between the two groups by using postoperative X-ray. The acetabular tilt angle (ATA) changes before and after operation in the computer-assisted osteotomy group were compared through 3D CT.Results:The follow-up duration was 2.3±0.2 (2.0 to 2.5) years in the computer-assisted osteotomy group and 2.8±0.15 (2.5 to 3.0) years in the conventional osteotomy group. The operative duration in the computer-assisted osteotomy group was 127±20.6 min, which was significantly longer ( t=4.657, P<0.001) than that in the conventional osteotomy group (103±13.2 min). Intraoperative bleeding was 157±17.5 ml in the computer-assisted osteotomy group and 151±15.3 ml in the conventional osteotomy group without significant difference between the two groups ( t=1.195, P=0.239). At 2 years after surgery, the JOA score of the hip joint in the computer-assisted osteotomy group (86.7±8.5 points) was like that (84.8±10.0 points) in the conventional osteotomy group ( t=0.628, P=0.533). At the last follow-up, the CE angle in the computer-assisted osteotomy group (36.8°±5.2°) was significantly larger than that (31.8°±4.4°) in the conventional osteotomy group ( t=3.414, P<0.001). There was statistically significant difference in term of AHI between the computer-assisted osteotomy group (85.8%±6.6%) and the conventional osteotomy group (80.4%±8.3%, t=2.284, P=0.028). AI was 23.5°±5.5° in the computer-assisted osteotomy group and 25.2°±4.2° in the conventional osteotomy group without significant difference ( t=-1.150, P=0.257). The ATA of the affected side was 12.3°±1.4° in the computer-assisted osteotomy group which was similar ( t=0.614, P=0.547) to that of the healthy side (11.8°±2.8°). Conclusion:Based on specific anatomical parameters, computer-assisted preoperative planning can not only directly simulate the process of osteotomy, but also produce individualized 3D printed guide plates. Compared with conventional Salter pelvic osteotomy, computer-assisted osteotomy can achieve accurate radiographic correction of the hip joint in children with DDH, resulting in a better matching relationship between the femoral head and acetabulum.